Thermostat assembly



May 17, 1938. H'. A. SMITH 2,117,578

THERMOSTAT ASSEMBLY Filed July 14, 1936 j? I 40 fn?? 56 vulahon V492? .36

" am ,L 58 24 4658 32 Patented May 17, 1938 UNITED STATES PATENT oEFicE :,nlsis THERMOSTAT AssEiimLY Howard A. Smith. St. Louis, Mo., alignor to Monarch Company Kmeerporationofhilaaonrl 84.11011, Mo., a

Application July 14. ma, sei-m No. 90,549

u claims (ci. zoo-iss) An object of my invention is to provide a thermostat assembly of simple construction, readily applicable to a wallie iron plate or the like, which is heated by a heating element, the thermostat being connected with the heating element to control the action thereof.

A further object is to provide a thermostat as- V sembiy which is designed with a minimum oi vertical dimensions when mounted against a wallie iron plate or the like, so that it can be mounted in the space available which, in the "low boy types of wallie irons, is rather limited.

Another object is to provide a thermostat assembly in which the bimetal element anda pair or contact spring arms are adjustable as to the temperature at which the contacts will be separated by means of a cam spaced laterally on the plate from the contact arms, and a rocker eiement which serves the purpose of transmitting the movement from the cam to the contact springs for 'adjusting them.

A further object is to provide a novel arrangement for supporting the contact springs on the plate to be heated with a minimum of parts and required time for assembLv.

With these and other objects in view, my invention consists in the construction, arrangement and combination of the vvarious parts of the device, whereby the objects contemplated are attained, as hereinafter more fully set forth, pointed out in my claims, and illustrated in the accompanying drawing, in which:

Figure l isa side elevation of lower half of a wallie iron, partof the casing thereof being broken away to show my thermostat assembly mounted on the bottom of the wallie plate or grid.

Figure 2 is a bottom plan view of the plate with the thermostat assembly mounted thereon.

Figure 3 is a sectional view on the line 3-2 of Figure 2 showing the rocker member which is an important feature of my invention.

Figure 4 is an enlarged sectional view on the line 4-4 of Figure 3 showing the mounting for a cam on a stud extending from the plate.

Figure 5 is a perspective view of the rocke member used in my assembly.

Figure 6 is an enlarged sectional view on the I -line 0-0 of Figure 2 showing the contact spring mounting; and

Figure 'l is a perspective view of an insulator used in connection therewith.

0n the accompanying drawing I have used the reference numeral I. to indicate a wallie iron grid or other plate or member to be heated by a resistance, heating element I2. This may be supported in the usual manner by a casing I4 having supporting feet I6. 'A tie rod Il is illustrated as extending from the bottom of the grid I0 through a cover plate 20 forming a bottom for the casing I4. A nut 22 holds the cover plate 5 and grid in their respective positions.

The heating element I2 may be supported in any suitable 'manner on the plate i0. By way of illustration I show the type of heating element disclosed in the Knapp et al., Patent No. 2,014,001 of September 10, 1935. It consists of a sheet metal l plate 24 with insulator 26 extending from the edge thereof. The outer ends of the insulators are notched to receive the heating element l2 and the plate 24 is retained in position with the. upper edges of the insulators contacting with the bottom of the plate I0 by a nut 2l on the bolt Il.

The actuating element for the thermostat assembly is a strip of bimetal 30 which has one end mounted between the central portion of the plate 20 24 and the plate I0, which is responsive to the temperature of the plate, as shown by dotted lines in Figure 3, upon a rise in temperature.

'Ihe remaining parts of the thermostat assembly, which I will now describe, I have mounted 25 on the plate 24 for convenience, although obviously if the heating element does not have a plate such as 24 to support it, these parts can be mounted on the plate il. Indirectly they are mounted on the plate I0 when carried by the plate 24, which in turn is mounted on the plate l0.

A projection in the form of a bolt 22 extends downwardly from the plates I0 and 24. On this projection a pair of insulators 24 are mounted, as well as a pair of contact springs 30 and 28 and the necessary terminal members, washers, nuts and the like to hold the parts properly assembled and in electrical connection. 'Ihe insulators 24 are provided with hub-like portions 40 which enter perforations of the springs 20 and 2l to electrically isolate them from the bolt 32.

Since the springs can turn on the hubs 4l, I have provided on each insulator a shoulder 42 to engage the edges of the springs 26 and 2l to prevent turning ofthe springs relative to the insulators. 'Ihe insulators in turn are prevented from turning relative .to the plates i0 and 24 by means of a projecti4 44 extending from the upon it will move the spring 36 upwardly in Figure 3 to the dotted position (downwardly in Figure 1), thus separating the contacts and breaking the circuit to the heating element I2.

The normal position of the spring 38a is shown by dotted lines in Figure 3. By moving this spring upwardly, the extension I8 is likewise moved upwardly so that it will take `a higher temperature of the plate I0 affecting the bimetal strip 30 to break the circuit. Accordingly by adjustingl the position of the spring 38, the setting of the thermostat can be adjusted.

To accomplish adjustment of the spring arms I provide a rocker element 50 having a pair of laterally spaced projections 52 adapted to enter perforations 54 in the plate 24. As obvious from- Figures 3 and 5, the rocker element can rock relative to the plate when the projections are in the perforations, since the projections have their lower ends tapered.

One end of the rocker element 50 is provided with insulating button 56 to engage the spring 38, while the other end has a rounded nose 58 adapted to be engaged by a cam element 60. The cam element 6D may be formed of sheet metal and is rotatable on a reduced portion 52 of a nut 64.

For swinging the cam 6 0 provide an operating arm 68 having a notched inner end 68. The notched inner end 68 fits against a shoulder fili of the nut $4 so that the arm 66 can be swung relative to the cam 60.

I provide means for locking the cam and arm relative to each other comprising an arcuate slot andk clamping bolt connection' illustrated at 'i2-TM. This constitutes a factory adjustment so that the thermostat can be properly set to secure the desired range of temperature operation.

The operating arm 66 extends through a slot 16 in the casing i@ so that it isengageable from the outside of the casing and can be moved from one end of the slot to the other by the user if desirable. One end of the slot will produce control of the temperature to a point where iight brown Waiies are baked by the waiiie iron, while the other end will produce dark brown Waiiies.

Obviously my thermostat assembly can be used in connection With electrical appliances other than the one shown on the drawing.

Also changes may be made in the construction and arrangement ofthe parts of my device Without departing from the real spirit and purpose of my invention, and it is my intention to cover by my claims any modied forms of structure or use of mechanical equivalents which may be reasonably included within their scope.

I claim as my invention:

1. For use with a plate or the like to be heated, a bimetal element responsive to the temperature of said plate, a contact structure carried by said plate and a cam element; said cam element being spaced laterally on said plate from said contact structure and a rocker element arranged substantially parallel to said plate, having a central portion pivoted relative thereto and its ends movable toward and away therefrom and coacting with said contact structure and cam element respectively.

2. For use With a plate or the like to be heated, a bimetal element responsive to the temperature of said plate, a contact structure carried by said plate and a cam element; said cam element being spaced laterally on said plate from said contact structure, a rocker element having a pair of 'laterally spaced projections, said plate having a pair of perforations receiving said projections and the ends of said rocker element coacting with said contact structure and cam element respectively to rock upon movement of the cam and thereby move the contact structure toward or away from said plate, said rocker element being located between said plate and said cam element and contact structure whereby said projections are retained in said perforations by said cam element and contact structure.

3. For use with a plate or the like to beheated, a bimetal element responsive to the temperature of said plate, a contact structure carried by said plate and a cam element; said cam element spaced laterally on said plate from said contact structure, a rocker element having a central portion pivoted relative to said plate and its ends coacting withA said contact structure and cam element respectively, said cam element being pivoted on an axis at substantially right angles to the plate, an arm element for operating said cam element, said arm element being pivoted relative to said plate, an arcuate slot in one of said elements and a clamping screw thru the other of said elements and thru said slot for locking said elements together against relative movement.

4. For use with a member to be heated, a bimetal element responsive to the temperature of said member, a pair of contact arms carried by said member and a cam element; said cam element spaced from said pair of contact arms, a rocker element having a central portion pivoted relative to said member, one of its ends coacting with said cam element and the other end thereof associated with said contact arms to adjust the position thereof.

5. For use with a member to be heated, a bimetal element responsive to the temperature of said member, a pair of contact arms carried by said member and a cam element; said cam element spaced from said pair of contact arms, a rocker element having a central portion pivoted relative to said member, one of its ends coacting with said cam element and the other end thereof associated with saidA contact arms to adjust the position thereof, said cam element being pivoted on one surface of said member and on an axis at substantially right angles to said surface, an oper ating arm pivoted to said cam element and means for locking said operating element and cam together against relative movement.

6. For use with a member to be heated, a bimetal element responsive to the temperature of said member and a contact structure comprising a pair of contact arms; means for mounting said arms on said member comprising a projection from said member, a pair of insulators thereon, each insulator having a shoulder and a notch, said member having a projection entering the notches of said insulators to prevent turning thereof relative to said member and said contact arms having their edges engaging said shoulder to prevent turning of the contact arms relative to the insulators.

7. For use With a member to be heated, a bimetal element responsive to the temperature of said member and a contact structure comprising a pair of contact arms; means for mounting said arms on said member comprising a projection from said member, a pair of insulators thereon, each insulator having a shoulder, said contact arms having their edges engaging said shoulder to prevent turning of the contact arms relative to the insulators and means for preventing turning of the insulators relative to said projections.

8. For use with amember to be heated, a bimetal element responsive to the temperature of said member and a contact structure comprising a pair of contact arms; means for mounting said arms on said member comprising a projection from said member, a pair of insulators thereon, each insulator having a notch, said member having a second projection entering said notch to prevent turning of said insulators relative to said member and means to prevent turning of said contact arms relative to said insulators.

9. For use with a member to be heated, an actuating element responsive to the temperature oi said member, a pair of contacts carried by said member and a cam element; said cam element being spaced from said pair of contacts and a rocker element having a central portion pivoted relative to said member, one of its ends coacting with said cam element and the other end thereof associated with said contacts to adjust the distance thereof from said member, said cam element being pivoted on one surface of said member and on an axis at substantially right angles to said surface, an operating arm pivoted to said cam element and means for locking said operating element and cam together against relative movement.

10. For use with a member to be heated, an actuating element responsive to the temperature of said member, a pair of contacts carried by said member and a cam element; said cam element being spaced from said pair of contacts and a rocker element having a pair of laterally spaced projections, said member having a pair of perforations receiving said projections and the ends of said rocker element coacting with said contacts and cam element respectively to rock upon movement of the cam element and thereby move the contact structure toward and away from said member.

11. For use with a member to be heated, an actuating element responsive to the temperature of said plate, a contact structure carried by said plate and a manually operable adjuster element; said element being spaced laterally on said plate from said contact structure and a rocker element having a central portion pivoted relative to said 

